Primary disconnect contacts



Aug. 19, 1958 A. s. cAswELL- 2,348,583

7 PRIMARY'DISCONNECT CONTACTS Filed Dec. 12, 1955 2 Sheets-Sheet 1 I l Mmz ws'mm Array/V675 Aug. 19, 1958 A. s. CASWELL PRIMARY DISCONNECT CONTACTS 2 Sheets-Sheet 2 Filed Dec.

INVENTOR. 4676 10? 5: C'flfw l- MM ent from the following description when taken United States Patent Ofiice.

2,848,583 Patented Aug. 19, 1958 Circuit l firealrer Company, Philadelphia, Pa., a corporatioribfiPennsylvania f" Application December 12, 1955,'Serial No. 552,614

4 Claims. (Cl. 200-163) Myflinvention relatesv to, primary disconnect contacts and in particular is directed to a novel arrangement wherein each of the, plurality of finger contacts is guided and retained within a single housing and provided with a separate biasing and retaining coil spring that is individual torthe finger contact. V

In electrical circuit interrupting apparatus such as high voltage circuit breakers, it is necessary to provide the equipment with primary disconnect contacts so that the circuit breaker can be selectively connected in the system which it is to protect.

In the prior art arrangement primary disconnect contacts have been constructed with, an arrangement wherein a common biasing means is used for a plurality of finger contacts. ,I-Iowever,,v in this arrangement the failure of the common biasing meanswould, result in the complete inoperativeness ofthe primary disconnect contact.

I have provided a novel primary disconnect contact assembly wherein a common housing is provided for all of the finger contacts, designed and constructed so that there are individual coil spring biasing means and retaining means for each of the finger contacts. Thus in the event of the failure of any one spring, there will still be sufficient pressure from the remaining springs toprovide a high pressure contact between the movable primary disconnect contactand the stationary primary contact. This invention is comprised of a movable primary disconnect contact wherein a common housing provides the function of being a positioning and retaining means for each of the plurality of contacts which are individually biased. 1

Accordingly, a primary object of my invention is to provide a novel primary disconnect contact having a plurality of finger contacts wherein each contact has an individual biasing means. I

Another object of my invention is to provide a primary disconnect contact for a circuit interrupter in which a common housing serves as a positioning, pivoting and retaining means for a plurality of finger contacts.

Still another object of my invention is to provide a primary disconnect contact which is relatively simple in design and requires a minimum number of components.

These and other objects of my invention will be apparin connection with the drawings in which:

Figure 1 is a perspective view of a typical circuit interrupter such as a circuit breaker containing the primary disconnect contacts of my invention.

Figure 2 is a side cross-sectional view of my novel primary disconnect contact. In this figure, the movable primary disconnect contact is in contact engagement with the stationary contact.

Figure 3 is a view taken in direction of arrows 33 of Figure 2 illustrating an end view of the housing and the manner in which it provides a retaining function for the plurality of finger contacts. v I I Figure 1 illustrates a typical application of my invention. The circuit interrupter may be of any type of circuit breaker well known in the art such as Patent No. 2,646,481i.issued July 21, 1953, to' the assigneeof the: instant application, and forms no part of my instant application. The circuit interrupter must be providedwith a pair of primary disconnectcontacts for each phase so that it can be removably connected in an electrical system which it is designed to protect. The plurality of the primary..disconnect contacts 11, whichare the objects of. my instant invention, are illustratedin theperspective View of Figure 1. A side cross-sectional view of any o ne'of the primary disconnect contacts 11 illustrated in Figure 1 is seen in Figure 2. .The purpose ofthe primary dis connect contact 11 is toprovide a removable electrical connectionbetween a first conductor. 12 and .a second conductor 13. The conductor12is associated with the circuit interrupter. 10 and movable therewith,- whereas the. primary conductor 13 is usually stationary-and associated with the system in which the circuit interrupter 10 ismaintainedto protect. The primary. disconnect contact 11 iscomprised Iofa housing 14, 15 having two sections. Intheillustrated view, the housing is comprised of the two sections 14, 15, although it will be apparent to those skillediin/the art that the concept. of my invention can also. be achieved by making .the housing in atsingle unit. The sections 14, 15 of the primaryndisconnect contact housing are basically. circular inconfigurationas, illustrated-in Figure 3 and are secured to eachother, as for example, by lbrazing. v, Thetstud 16 not .only passes through the two sections 14, .15 ofthe housing, but alsois in threaded engagement with the first primary conductor 12 so that the housings 14,Il15.ar'e mechanicallysecured theretowThe nut 17 serveslas a retaining means to secure the sections 14, 15 to the primary conductor .12. l t

The stud 16 has a self lockinginut 17 which, in conjunction with washers, assumes that the disconnect contact assembly remains in electrical contact and follows thecircuit breaker stud 12. There is infact a loose fit between the primary disconnect contact assembly 11 and the stud 12 to compensatefor misalignment; Since it is desirable to provide a loose fit between-thesetwo members, the member 17 is a self lockingnut. i a

.The two sections 14, 15 are substantially identicalin construction. As illustrated in the tend cross-sectional view :of Figure; 3, the housing section is provided with -a pluralityiof'radially disposed slots 18whichserve as-a positioning, pivoting and. retaining means for the finger contact. '19 associated therewith. The lower vsur-face 20 of each of the radially disposed-slots 18 serves asa pivot and astop point for the finger contact'19L r a viThe ilowerwsurface 20 serves as a stop for the finger contacts 20 when the primarydisconnect contact assembly 11 is disengaged from the stationary stud 13. That is, the coil springs 26--27 bias the finger contactZG radially inward toward the center of the assembly against the stop surface 20. Since electrical engagement between the. contact fingers 19 and the stationary stud 13 will move these fingers radially outward against the bias of coil spring 26, the stop surface 20 controls the lift of contact fingers 19 when they are forced into electricalengagement. The greater the lift required for each finger contact 19, the greaterlwill be the entering force required for electrical engagement between the primary contact assembly and stud 13. 7

Since both sections 14 and 15 are substantially identical, they each have a pivot point 20"for the finger contact 19 which is positioned within the'slots 18 of the two sections 14 and 15. That is, for each slot 18 in the contact finger 19 associated with these slots illustrated in Figure 2.

The finger contact 19 is comprised of a substantially fiat conducting member having a contact surface 21 and 22 as well as two recessed sections 23 for positioning on the pivot points 20 of the slots 18. The opposite side of the finger contact 19 is provided with a protruding sections 24 and 25 to receive coil springs 26 and 27L 3 As best seen in Figures 2 and 3, the coil springs 26 and 27 are positioned between one surface of the housing 14, and the finger contact 19. The protruding section, such as 24 and 25, which as finger contact 19 serves as a partial positioning and retaining means for its respective coil spring 26 and 27.

There are a plurality of coil springs 27 on the side of the pivot toward the first conductor 12 to bias the associated finger contact 19 into engagement with the primary conductor 12. That is, the conducting surface 21 of the finger contact 19 is brought into high pressure electrical contact with the primary conductor 12. When the primary disconnect contact 11 is moved into engagement with the Second primary conductor 13, the coil spring 26 serves to bias the contact surface 22 of the finger contact 19 into high pressure electrical engagement with the second primary conductor 13.

Thus, it will be noted that the primary disconnect contact 11 of my invention is comprised basically of a single housing 14, 15 having a plurality of radially disposed slots 18 which serve as positioning, pivotal and guiding means for a plurality of finger contacts 19. Furthermore, each of the finger contacts 19 is provided with its individual biasing means such as coil spring 27 to bias it into high pressure electrical engagement with a first primary conductor to which the housing is mechanically connected, and also a second series of coil springs 26 to bias the same plurality of finger contacts 19 into high pressure electrical engagement with the second primary conductor 13.

Thus, in the event any one of the plurality of coil biasing springs 26, 27 should fail, there will be a suflicient force from the remaining springs on other finger contacts 19 to maintain high pressure electrical engagement. That is, since each coil spring 26 maintains its individual finger contact 19 in high pressure contact with stud 13, loss of any one spring 26 merely causes loss of only one point of high pressure contact. It is further noted that when the primary disconnect contact 11 is removed from engagement with thesecond primary conductor 13, that the coil springs 27 combine with pivotal means 20 which serve to retain finger contacts 19 in position. Since there are a plurality of finger contacts 19, each of which is provided with individual biasing means, the force required on each one is relatively small. It is further noted that the configuration of the finger contacts 19 positions and retains the contact in place in cooperation with the plurality of slots 18, and. furthermore, positions andretains a plurality of biasing springs 26, 27 in place.

In addition to all of the above noted advantages of the instant invention, it will be noted that the simple housing arrangement 14 and 15 serves not only to position, pivot and retain the finger contacts 19, but also as a base for the plurality of biasing springs 26, 27 so that the entire unit is compact and requires a minimum of operating parts in the present invention. The housing 14, 15 is made of a conducting metallic material so that it will serve as a shielding ring for the contacts to properly distribute potential about to increase flash over voltage. Furthermore, in the event the primary disconnect contact 11 with its associated primary conductor 12 is slightly misaligned from the second primary conductor 13, there will, nevertheless, be automatic alignment due to the individual flexibility of the plurality of finger contacts 19. As heretofore noted, the stud 16 and self locking nut 17 provides a loose fit connection between the primary disconnect contact assembly 11 and the conductor 12. Hence, the entire assembly 11 is free to move with respect to the conductors 12 and 13 to compensate for '4 large degrees of misalignment between conductors 12 and 13 along the longitudinal center line.

The multiple finger arrangement on primary disconnect contact 11 are radially disposed with individual biasing means so that there will be a uniform high pressure between the cooperating contacts surface 21, 22 and their respective conductors 12 and 13.

In the foregoing I have described my invention only in connection with preferred embodiments thereof. Since many variations and modifications of the principles of my invention Within the scope of the description herein are obvious, I prefer to be bound not by the specific disclosure herein but only by the appended claims.

I claim:

1. A primary disconnect contact for a circuit interrupter comprised of a housing and a plurality of finger contacts, said housing being comprised of a first section and a second section positioned back to back and each section having a plurality of radially disposed slots for receiving said plurality of finger contacts, a spring biasing means individual to each end of said finger contacts, each of said spring biasing means positioned within said housing; each of said finger contacts associated with two of said radially disposed slots; a surface of said radially disposed slots serving as a piovt point and stop to control the amount of finger deflection and load required to engage the assembled contact for said finger contacts.

2. A primary disconnect contact for a removable connection between a first and second primary conductor; said primary disconnect contact being comprised of a housing, a plurality of finger contacts and a plurality of coil springs; said housing being mechanically connected to said first primary conductor by a first means; said housing having a plurality of radially disposed slots, each of said plurality of finger contacts being associated with one of said radially disposed slots; said radially disposed slots being constructed to provide a guide and pivot means for said plurality of finger contacts; one of said plurality of coil springs being associated with each of said plurality of finger contacts and positioned within said housing on the side of said pivot toward said first conductor to thereby individually bias each of said finger contacts into engagement with said first conductor; one of said plurality of coil springs being associated witheach of said plurality of finger contacts and positioned within said housing on the side of said pivot toward said second conductor to thereby individually bias each of said finger contacts into engagement with said second conductor; said first means being comprised of a stud and a self locking nut threaded thereon; said first means providing a mechanical connection which permits said housing to move laterally with respect to the longitudinal axis of said first primary conductor to thereby compensate for axial misalignment between said first and second primary conductors.

3. A primary disconnect contact for a removable connection between a first and second primary conductor; said primary disconnect contact being comprised of a housing, a plurality of finger contacts and a plurality of coil springs; said housing being mechanically connected to said first primary conductor; said housing being comprised of a first section and a second section positioned back to back and each section having a plurality of ra dially disposed slots, each of said plurality of finger contacts being associated with one of said radially disposed slots in said first section and one of said radially disposed slots in said second section; said radially disposed slots being constructed to provide a guide and pivot means for said plurality of finger contacts; one of said plurality of coil springs being associated with each of said plurality of finger contacts and positioned within said first section on the side of said pivot toward said first conductor to thereby individually bias each of said finger contacts into engagement with said first conductor; one of said plurality of coil springs being associated with each of said plurality of finger contacts and positioned within said second section on the side of said pivot toward said second conductor to thereby individually bias each of said finger contacts into engagement with said second conductor;'said first means being comprised of a stud and a self locking nut threaded thereon; said first means providing a mechanical connection which permits said housing to move laterally With respect to the longitudinal axis of said first primary conductor to thereby compensate for axial misalignment between said first and second primary conductors.

4. A primary disconnect contact for a circuit interrupter comprised of a housing and a plurality of finger contacts, said housing being comprised of a first section and a second section positioned back to back and each section having a plurality of radially disposed slots for receiving said plurality of finger contacts, a biasing means individual to each of said finger contacts, each of said 6. biasing means positioned within said housing; each of said finger contacts associated with two of said radially disposed slots; a surface of said radially disposed slots serving as a pivot point and stop to control the amount of finger deflection and load required to engage the assembled contact for said finger contacts; each of said biasing means being comprised of a first spring and a second spring spaced thereform; said first spring bearing against a first end of its associated finger and said second spring bearing against a second end of its associated finger to bias said finger toward the center of said housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,300,983 Hayford Nov. 3, 1942 2,376,818 Rubel May 22, 1945 2,600,211 Cushing June 10, 1952 

